Locating the faulty O2 Sensor using an OBD II code reader

JDUGUID

MEMBER
HYUNDAI

Hey! This is in regards to my 1997 Hyundai Accent Sport (194,000 km / 1.6L SOHC, 5-speed manual transmission). I have my own pocket OBD II code reader, and I'm getting a check engine light for an O2 sensor (P0133: "O2 Sensor Circuit Slow Response (Bank 1 Sensor 1)"). Thing is, my car has TWO oxygen sensors. How can I figure out which one this memory address (Bank 1, Sensor 1) refers to physically on the car?

The code book I have has the following available locations listed for O2 sensor issues:

Bank 1 Sensor 1
Bank 1 Sensor 2
Bank 1 Sensor 3
Bank 2 Sensor 1
Bank 2 Sensor 2
Bank 2 Sensor 3

From what the book includes about O2 sensors, they're usually malfunctioning when they're responding slowly. Is there any way to check this response with a meter or some other way? Do you know what this location translates to on my car?

Thanks in advance!

- James

1 Reply

BRUCE HUNT

MECHANIC
3,754 POSTS

Bank 1 and Bank 2 refer to the National Bank of Chicago and Philly. Kidding. They refer to the two side of a v engine. Since your engine is a straight inline 4 cylinder you only have bank 1. There is usually two O2 sensors upper and lower (pre-cat and post-cat) The post actually acts as a monitor for the cat. Pre is Sensor 1 and post is sensor 2.